How do you do that?

22nd May 2013
When I first developed this website, I wanted some clean, white-background images to use on the home page. Since then, I've been trying to improve the process of producing these; both to add new images to my website and also to sell as "stock" images. I've had a few people ask me what my process is for producing these, so I've produced this blog post to explain my technique.

Over the past few years and after taking thousands of invertebrate images, I've found that on some occasions, invertebrates can be very accommodating when it comes to "modelling" for me. This can be because as a species, they're generally not particularly active, on particular occasions (early or late in the day or any time when it's cold) they become rather inactive, or for anything, if you're very careful, they can be picked up and transferred to another location. It's important that after any such transfers, any subjects are returned to where they were found.

I generally have an A4 sheet of white foam-board with my camera equipment, just in case an opportunity arises. If you just leave it near an area where insects are active, they will often crawl or fly onto it of their own accord! For this Blog post I'll describe photographing a Cacoxenus indagator fly. These parasitic flies have a liking for solitary bee nests, particularly those of the Red Mason Bee (Osmia bicornis). I have a "bee hotel" in the garden and there are lots of these flies investigating the Red Mason Bee nests. They seem to "roost" overnight on the bee hotel and if the morning is cold, I've found that they cn be carefully lifted off with a watercolour brush and transferred to the white card. They'll scuttle around for a few seconds and then quieten down.

The first photograph shows my standard camera configuration for insect macro photography. This includes a Canon DSLR body, a Canon MP-E 65mm Macro lens and a Canon MT24-EX TwinLite flash (with added diffusers). Any macro setup will work, but additional lighting from flash definitely makes life easier. I will typically set the camera to Manual, with a shutter speed of 1/250th second (this is the x-sync speed for my camera), an aperture of between F8 and F11 (depending on subject) and ISO 100. Without the flash, this would not register any "ambient" light (or very little). Virtually all light comes from the flash and as such, I can control it properly. Here, the camera is resting on a beanbag and the white card is raised on a couple of books.

Digital camera metering systems are calibrated expecting that all the tones in an image will average out to a mid-grey (known as 18% grey). That means that very light scenes (snow scenes etc) will often turn out darker than they should, and very dark scenes will turn out paler. I use Flash Exposure Compensation (FEC) to adjust for this. I know that with my camera setup, white-background shots will require up to two stops of positive FEC to get the background almost white. I dial this in on the camera body before I start; either one and two thirds, or two full stops, before I start.


Here's one of the Cacoxenus indagator images opened in Adobe Photoshop Elements. The background is very pale, but not pure white. I've opened up the Levels dialogue and you can see from the histogram, that there is a large "peak" near the right-hand side. The histogram is the same os the one your camera displays, showing black tones to the left, white tones to the right, and all the mid-tones in between.


To lighten the background, here I've chosen the White Picker tool and clicked on the background just above the fly. The clicked area has now been set as pure white and the background is just about as I require it. You will see that the "peak" in the histogram is now tight against the right-hand side. Some of the background at the top on the image may still be slightly grey at this point, as this was the area furthest from the flash. This can be corrected using the Dodge tool. I set this to 100% and to Dodge Highlights only, and sweep it over any remaining grey areas.


The background should now be acceptable and it's time to tidy-up any blemishes/sensor spots in the shadow areas and on the subject. I mainly use use the Spot Healing Brush for this, set to Proximity Match. This together with the Clone Tool, will correct any problems. Because I use some of my images to sell as "stock", I will spend time on these "corrections". The important thing for me, is to get the shadows looking reasonably smooth.


It's now time to add the "finishing touches" to the image. For this one, I lightened the shadows a little, cropped the image and then sharpened it. The goal is to get the subject looking as it did through the camera viewfinder. This is a version with a boder added. I usually add a border and copyright notice to any images that I post on Flickr. This all might seem a bit "long-winded", but it quite quick once you're used to the processes. The important thing is to the get the image as near-correct as possible in camera. For me, Exposure Compensation or Flash Exposure Compensation is the key to this.

Comments

Photo comment By Amelia: Very interesting post for me. Its the sort of thing I would like to try. I have done it with flash indoors and available light outdoors on a sheet of white paper but of course I'd love to get that sharpness. It is nice to follow how its done. The flash equipment is interesting too.

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